Language

Available as of Camel 2.5

The language component allows you to send Exchange to an endpoint which executes a script by any of the supported Languages in Camel. By having a component to execute language scripts, it allows more dynamic routing capabilities. For example by using the Routing Slip or Dynamic Router EIPs you can send messages to language endpoints where the script is dynamic defined as well.

This component is provided out of the box in camel-core and hence no additional JARs is needed. You only have to include additional Camel components if the language of choice mandates it, such as using Groovy or JavaScript languages.

URI format

And from Camel 2.11 onwards you can refer to an external resource for the script using same notation as supported by the other Languages in Camel

URI Options

The component supports the following options.

Name

Default Value

Type

Description

languageName

null

String

The name of the Language to use, such as simple, groovy, javascript etc. This option is mandatory.

script

null

String

The script to execute.

transform

true

boolean

Whether or not the result of the script should be used as the new message body. By setting to false the script is executed but the result of the script is discarded.

contentCache

true

boolean

Camel 2.9: Whether to cache the script if loaded from a resource. Note: from Camel 2.10.3 a cached script can be forced to reload at runtime via JMX using the clearContentCache operation.

cacheScript

false

boolean

Camel 2.13/2.12.2/2.11.3: Whether to cache the compiled script. Turning this option on can gain performance as the script is only compiled/created once, and reuse when processing Camel messages. But this may cause side-effects with data left from previous evaluation spills into the next, and concurrency issues as well. If the script being evaluated is idempotent then this option can be turned on.

binary

false

boolean

Camel 2.14.1: Whether the script is binary content. This is intended to be used for loading resources using the Constant language, such as loading binary files.

Message Headers

The following message headers can be used to affect the behavior of the component

Header

Description

CamelLanguageScript

The script to execute provided in the header. Takes precedence over script configured on the endpoint.

Examples

In case you want to convert the message body type you can do this as well:

You can also use the Groovy language, such as this example where the input message will by multiplied with 2:

You can also provide the script as a header as shown below. Here we use XPath language to extract the text from the <foo> tag.

Loading scripts from resources

Available as of Camel 2.9

You can specify a resource uri for a script to load in either the endpoint uri, or in the Exchange.LANGUAGE_SCRIPT header. The uri must start with one of the following schemes: file:, classpath:, or http:

For example to load a script from the classpath:

By default the script is loaded once and cached. However you can disable the contentCache option and have the script loaded on each evaluation. For example if the file myscript.txt is changed on disk, then the updated script is used:

From Camel 2.11 onwards you can refer to the resource similar to the other Languages in Camel by prefixing with "resource:" as shown below: